Scintillating plastic is the lightning rod of a particle detector, collecting the
energy from particle collisions, converting it into light and transporting the
light to electronic readouts for transformation into digital signals that produce
scientific data. Few particle physics experiments could exist without it.

Like virtually every piece of equipment in
high-energy physics research, the new 70-foot
extruder for scintillating plastic at Lab 5 offers
new prospects for using everyday materials
in the search for discoveries in the science
of matter, energy, space and time. And like
virtually every piece of equipment in highenergy
physics research, the new 70-foot
extruder will make its contributions because
of technicians and operators who have used
their skill, experience and savvy to get it
delivered, set up and running.

"You just don't turn a key and get plastic,"
said Jerry Zimmerman, of the Technical
Centers department in Fermilab's Particle
Physics Division.

The $550,000 assemblage of mixers, dies, and cooling tanks for turning
molten mixtures into precision plastic was funded by Northern Illinois
University and sited at Fermilab for the Northern Illinois Center for Accelerator
and Detector Development.

"Fermilab is a world-class research facility, and NIU now has the equipment
to produce novel scintillating detectors, so the collaboration makes perfect
sense," said NIU physicist and NICADD codirector Jerry Blazey, who also
serves as cospokesperson at DZero.

The millions of feet of scintillating plastic required for such experiments as the
Main Injector Neutrino Oscillation Search (MINOS) will still be made for the
lab by commercial firms.

But trying out new methods and materials could run $1,500 a day on similar
equipment at a commercial firm. The Lab 5 extruder is a research tool, aimed
at producing data on different scintillator compositions, and developing ways
to improve production. The NIU Mechanical Engineering Department will
provide two professors and several students to work on designs for extrusion
dies and to develop software packages for simulating the fluid flow.

"It's a great tool for students," said materials scientist Anna Pla-Dalmau,
leader of PPD's Scintillation Detector Development group and a specialist
in scintillator for her 16 years at the lab. "It offers students a specific hands-
on approach. They can run simulations, and they
can see what comes out of the die."

But setting up the assembly line and handling the
plastic that runs through it are tasks reserved for
the seasoned pros like technicians Zimmerman
and Chuck Serritella.

"When the machinery was delivered in February,
there were so many mechanical and electronic
challenges," said research scientist Viktor Rykalin
of NIU, who coordinates the R&D effort for NICADD.
"Jerry and Chuck did incredible work to get this
apparatus up and running."

What was the biggest challenge?

"I can't think of one big doozie, just lots of middlesized
ones," Zimmerman said. "Setting up the
dryer was maybe the biggest, since it was taller
then the crane in the building. The riggers had
to use a multistep approach to get it on to the
platform."

Followed by a multistep approach to get it running
smoothly, from pellets dropped down a funnel to
precise scientific instrumentation appearing at
the other end.

"By being involved with every aspect of the
installation and setup," Zimmerman said, "we've
learned almost every square inch of the machine.
We can apply that knowledge to getting the best
plastic. Our job as Operator Technicians is to
improve the processes, not just do to them."

Once the plastic content and feed rate have been
decided, and the pellets have been dropped and
melted, every inch of the process depends on hands-on skill. Serritella explained that operators wear thick insulated leather gloves that have been
soaked in water. The molten plastic begins its trek
through the die and the cooling tanks at 200 degrees
Celsius. Yet the production demands a fine touch by
the operatorseven through thick gloves.

"It comes out molten. What you have to do is cut it
off, then shape it and feed it into the cooling baths,"
Serritella said. "You continue feeding it over these
rollers in the tanks of cooling water. The whole
70-foot line is done that way. Next there's a tank
of water where it's sprayed to cool it more. Then
there's an air bath, then it moves into a puller that
maintains the shape by pulling at the right rate. But
it's a "feel" thing. If you pull too hard, you'll break it
and it'll run back down on the floor. If you pull too
slowly, it'll jam up and end up on floor again. The
machine is coordinated by computer. Hopefully,
when you get to the puller, it takes over and pulls
at the proper speed. It's still warm but completely
solid. You move it onto the table where it's cut to
pre-determined lengths."

For MINOS, those lengths reached 11 meters (about
35 feet), and Pla-Dalmau said possible lengths are
limited only by transportation requirements. The future
holds the promise of increased computerization for
efficient operation and improved tolerances.

"Our goal is to build detectors for the next generation
of particle experiments," said Fermilab physicist
Alan Bross.

Making those detectors for the future of particle
physics will always depend on pairs of skilled
hands.